This invention relates to a medical devices and techniques, and more particularly to a biopsy needle-type probe that is adapted for cutting and removing multiple tissue cores from a single needle penetration, with the tissue extraction accomplished by a looped flow of high-pressure media.
To biopsy tissue from a targeted site in the interior of a patient""s body, for example in a breast biopsy, the various prior art methods include (i) use of a biopsy needle; (ii) fine needle aspiration in a stereoatatic needle localizing assembly, or (iii) a skin incision and surgical removal of tissue from the targeted site. When using a biopsy needle, such as a True-Cut(copyright) needle, the tissue sample is often smaller than desired for biopsy purposes. Fine needle aspiration using a standard 14 Ga. needle also results in small tissue samples. Open skin incisions are undesirable due to scarring.
What is needed is a tissue cutting probe (i) that can excise and remove tissue through a very small diameter needle probe to provide a minimally invasive procedure; (ii) that can take multiple cores from a single needle penetration; (iii) that can be used manually or m conjunction with a stereotactic locking systen; (iv) that can be scaled upward in dimension to perform a stereotactic lumpectomy procedure by successive removal of tissue cores; and (v) that is inexpensive to manufacture and is therefore disposable.
The present invention comprises an elongate sleeve assembly that can be introduced into the interior of a patient""s body for excising and removing small tissue volumes in a minimally invasive procedure. The system of the invention provides a novel pressurization system that uses high positive fluid pressures to push excised tissue from the working end of a probe, in contrast to prior art systems that attempt to pull or aspirate tissue from a working end. The use of high pressure fluid flows to carry tissue along a passageway allows for a very small diameter tissue-extracting lumen. The prior art vacuum sources cannot develop sufficiently strong suction forces to move an excised tissue core within a small diameter tissue-extracting lumen.
In a preferred embodiment, the system provides an elongate needle-type member that carries a looped inflow-outflow passageway system. The distal working end of the needle assembly has a tissue-receiving opening in a wall surrounding a distalmost chamber of a passageway that receives a tissue volume pressed into the opening. A moveable blade member cooperates with the opening to excise the tissue volume captured in the tissue-receiving opening. At the same time, the blade member functions as a valve to alter the opening between a first open position and said second closed position. The looped passageway system comprises (i) an outflow passageway extending between a proximal open end (in the needle handle) and the distalmost chamber thereof, and (ii) an inflow passageway extending between an open proximal end (in the needle handle) and a distal terminus thereof that communicates with the distalmost chamber of the outflow passageway. The pressurization source is connected to the proximal end of the inflow passageway.
In operation, the needle is introduced to the targeted site and the blade member is thereafter actuated to excise tissue engaged within the tissue-receiving opening. The blade member is maintained in the second position which closes off the tissue-receiving opening. The pressurization source is then actuated which delivers a pulse of high pressure fluid flow through the looped inflow and outflow passageways to push the excise tissue from the needle into a collector at the exterior of the patient""s body. The excising and extracting steps can be repeated to obtain successive tissue cores from the targeted site with the needle only penetrating to the site once.
The present invention advantageously utilizes positive pressure media flows to transport tissue cores along a very small diameter tissue-extracting lumen, rather than using a negative pressure (vacuum) which has limited effectiveness in a small diameter lumen.
The present invention advantageously can extract multiple tissue cores from a single needle penetration.
The present invention can be coupled to a stereotactic needle localizing assembly for excising relatively large tissue volumes, as in a lumpectomy procedure.
Additional objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.